Pressure gauge



Sept. 24, 1929. H. H. MOTHERAL 78 PRESSURE GAUGE Filed May 1928 2Sheets-Sheet l M/ZII 4 I 1 I 12/ /a a3 INVENTOR WITNESSI ATTORNEY P1929- H. H. MOTHERAL 1,729,178

PRESSURE GAUGE Filed May 8, 1928 2 Sheets-Sheet 2 35 if $91M) fif Marla122620 INVENTOR ATTORNEY \IITNESSzZ/ g g Patented Sept. 24, 1929 UNITEDSTATES PATENT OFFICE HARRY HOTHEBAL, OF YONKEBS, NEW YORK rnnssnnn'GAUGE Application filed lay a, 1928. Serial 10. 276,185.

5 The primary object of the invention resides in a )ressure gaugewhichindicates on one dial y one indicating hand the difference in thepressure of two separate pressures, such as steam and water. a

vide a pressure gauge that will indicate the pressure of one elementindependent of the other when desired. Another object is to provide apressure 15 gauge with equalizing means which holds the of which will bereadily understood and appreciated by those skilled in the art to whichthe invention pertains.

The invention will from the accompanying drawings illustrating theinvention in its preferred form, and the following detailed descriptionof the construction therein shown. 1

In the drawings 1 Figure 1 is a. perspective view of my differentialpressure gauge.

Figure 2 is a front view of the same with i flexible tube 13 by a link43 pivoted to a lever 4 the dial removed.

Figure 3 is a vertical transverse sectional view taken on the line 3-3of Figure 2.

Figure 4 is a horizontal sectional view taken on the line 44 of Figure2. v Figure 5 is a perspective view of the operating parts per se in aseparated condition.

Referring to the drawings by reference characters, the numeraldesignates my improved differential pressure gauge in its entirety whichincludes an equalizing device 11 Another object of the invention is topro be clearly understood pivotally attached to the free ends of a pairof flat tubular curved flexible members 12 and 13, extending fromheaders 14 and 15 mounted on the inner side wall of a casing 16. A

dial 17 closes the front of the casing, while the sets of indicia A andB on the same, and an indicating hand 18 are rotected by the usual rim19 and glass ,20 which provide a space 21 between the dial 17 and theglass 20 to allow the indicating hand to oscillate.

The equalizing device 11 comprises avbearing support 21' mountedcentrally upon the back wall of the casing 16 by screws or the like 22,and rotating within the bearing support is an arbor 23 which extendsthrough an opening 24 in the center of the dial 17' and carries theindicating hand 18. Integral with the arbor 23 is a gear 25 which mesheswith teeth 26'of a segment 27 swingably mounted on a shaft 28 within aframe 29 which in turn swings upon the arbor 23. The frame 29 is pivotson the arbor 23 having a threaded pin 38 extending through a slot 39provided in one of the ends of the arm 36 and locked in an adjustedposition by a lock nut 40, the free end of the pin sliding within a slot41 provided in the tail of the segment 27. To allow the arm. 36 toextend beyond the pivot point of the segment 27, I provide therein anarouate sha ed slot 42 which allows the arm to swing t e segment to afurtherposition. The opposite end of the arm 36 is swung by the 44 whichhas one end-pivoted to the side wall of the casing as at 45 while theopposite end is slidably'connected to the arm-36 by slot and pin 46 and47 respectively. g

The headers 14 and 15 which are mounted diametrically opposite eachother on the inner side wall of the casing have threaded bores 50 toreceive the threaded end of pipes 51 and 52 which convey the medium suchas steam and water respectively, of which the 1 will tend to swing to astraightened position,-

pressures and pressure differences are to be measured.

Should it be desired to know the exact pressure pound of water, a valve,not shown, on the steam line is closed and a valve on the .water lineopened, allowing the water to flow through the pipe 52 into the headerto the flexible tube 13 which, when under, pressure there fore the freeend of the same pulls'on the links 43 swinging the lever 44, lifting thearm 36 which is pivoted on the arbor 23 swinging the free end of'the armin a downward position carrying the tail of the segment 27 down causingthe spindle to turn in a counter clockwise direction as the teeth 26 onthe segment 27 are in mesh with the gear on the arbor. This position ofthe parts is shown in Figure 2 of the drawings in dotted lines. Theindicating hand 18, which is attached to the free end of the arbor, willpoint to the number of 'pounds pressure on the left hand side of thezero mark co-acting with the scale of gradua tions B.

To read the exact pressure of the steam independent of that of thewater, the. valve in the water line is closed, releasing the pressure onthe gauge spring 12 and allowing the same to return to normal positionas shown in full lines in Figure 2. A valve on the steam line is thenopened and as the steam travels through the header 14 into the gaugespring 12 the pressure will force the free end of the spring toward thewall of the casing, the link which is pivoted at one end to the free endof the gauge spring 12 and the opposite end to the lever33 will tend toswing the free end of the lever in a downward direction which in turnswings the outer end of the carriage 29 in a downward direction also. Itwill be readily seen that the tail of the segment 27 will-he held by thepin 38 on the arm 36 while the shaft 28, on which the segment pivots,moves on an arc of the centre arbor. During'this operation. the arbor 23will be turned in the opposite direction to that shown in dotted linesin Figure 2 swinging the indicat- '--ing hand in a clock-wise directionto indicate and measure the number of pounds pressure of steam.

To determine the difference in pressu-rcof both steam and water, thevalve inthe water line is again opened allowing the water to flow intothe flexible tube 13 operating the parts as described above, turning theindicator in a counter clock-wise direction and should the pressure ofthe water he the same as that of the steam the indicator will stop onthe zero-inark. Should the pressure of the water he, say ten pounds lessthan that of the steam pressure, the indicating hand will stop at ten onthe right hand side of the zero mark.- Although I have explained theoperation of the gauge by water and steam. the same will operate by anytwo mediums under pressure. a

'While I have described what I deem to be the most desirableembodimentof my invention, itis obvious that many of the details may be variedwithout in any way departing from the spirit ofmy invention, and Itherefore do not limit'mys elf to the exact details-of constructionherein set forth nor to anything less than the whole of my inventionlimited onl by the appended'claims.

\ hat is claimed as new is:-

1. In a diiferentia. pressure gauge, a casing, pressure pipes enteringsaid casing, Bourdonvtubes connected to the respective pipes, an arborhaving a pinion and an indicator member fixed thereon, means forrotatabl supporting the arbor in the casing, a roc er arm pivoted onsaid arbor, a frame pivoted on said arbor, a stud carried by said frameand extending through an opening in said rocker arm, a gear segmentswingingly mounted on said stud and meshing with said pinion, one endofsaid rocker arm bein connected to the closed end of one of sai tujbes bya plurality of pivoted links, the ot ier end having sliding pivotalconnection with the segment, whereby outward flexing of one of saidBourdon tubes will actuate the said rocker arm to impart movement tosaid gear segment in one direction b reason of a pin and slotarrangement there tween, and a plurality of operative] connected linksbetween the closed end 0 the other of saids 2. A differential pressuregau e consist.

ing of a pair of Bourdon tubes, a uid charging connection for each tube,a bearing support, an indicator carrying shaft pivoted to turn on saidsupport, a pinion gear on said shaft, a frame pivoted to swing on saidshaft, a gear segment pivoted to swing on the pivoted frame and engagingthe inion, means havin ivotal connection wit one end of one of t eBourdon tubes and pivotal connection with the r segment, and a memherhaving ivo connection with the other Bourdon tu and ivotal connectionwith the ivoted frame, w ereby the movement of one cater carrying shaftin one direction will be modified by the movement of the other Bourdontube exerted to turn the shaft in the opposite direction, while allowingboth tubes unrestrained freedom of movement,

In testimony whereof I have aflixed my signature.

HARRY MOTHERAL.

ourdon tube exerted to turn said indi-

